====== DCDC ======

DCDC power mode needs external coil connected to DCC pin.
Without coil and DCDC enable strange issues occurs:
  * random ''z_arm_usage_fault'' in Zephyr based apps.
  * app startup stuck in ''lfclk_spinwait()''
  * everything works with J-Link connected :)

References:
  * [[https://devzone.nordicsemi.com/f/nordic-q-a/77570/zephyr-project-on-a-custom-board-wont-start-up-after-removing-debugger|Zephyr project on a custom board wont' start up after removing debugge]]
  * [[https://devzone.nordicsemi.com/f/nordic-q-a/97863/nrf52832-application-won-t-start-without-rtt-console|nRF52832 application won't start without RTT console]]
  * [[https://devzone.nordicsemi.com/f/nordic-q-a/102766/interesting-issue-with-board-configuration---application-wont-start-unless-kickstarted-by-rtt-or-debugger|Interesting Issue with board configuration - application wont start unless "kickstarted" by RTT or debugger.]]
  * [[https://github.com/NordicSemiconductor/Nordic-Thingy52-FW/issues/28|It doesn't run without connect j-link viewer]]